The goal of this research program is the investigation of reproduction, oogenesis, and early embryonic development with an emphasis on the molecular mechanisms that control genetic activity. A variety of methods and living systems will be utilized with the central technical theme of nucleic acid sequence comparison by hybridization. We will continue to investigate the molecular characteristics of the RNA transcribed during oogenesis, and the fate and function of this RNA. The fundamental problem is the molecular mechanism of gene regulation in the early embryo. Our recent studies have demonstrated a pattern of order in the sequence arrangement of the genome. This is almost certainly related to the basic mechanism of gene regulation. In this project we will develop decisive tests of the gene regulation model we have proposed. The project is designed to uncover basic new information about transcriptional regulation in the reproductive process. Specifically this proposal will include: extension and generalization to several species of our theories of genomic sequence arrangement and the interspersion of repetitive and non-repetitive DNA sequences; analysis of sequence organization and the role in early development of oocyte RNA's of Xenopus, sea urchin, and Urechis; and tests of asymmetric distribution of RNA transcripts in the cytoplasm of early embryos, as a possible specific explanation for the universal phenomenon of cytoplasmic localization of morphogenetic potential. BIBLIOGRAPHIC REFERENCES: Chamberlin, M.E., Britten, R.J., and Davidson, E.H. Sequence organization Xenopus DNA studied by the electron microscope. J. Mol. Biol. 96, 317-333, 1975. Davidson, E.H., Hough, B.R., Klein, W.H., and Britten, R.J. Structural genes adjacent to interspersed repetitive DNA sequences. Cell 4, 217-238, 1975.